In recent years, image and video signal compression techniques have become more and more important in multimedia data storage and transmission, and people demand more for the efficiency and robustness in data storage and transmission. A scalable video coding (SVC) system is extended from the H.264/AVC image encoding standard. This SVC system has the advantages of having low bit output rate, high error resilience, and network-friendly nature, and adopts the concept of layered coding to send bit-streams of different characteristics to an IP network. The SVC system provides three types of scalability, namely, spatial, temporal and quality scalability. According to the SVC system, when an image frame is received, the image frame is down-sampled to generate a base layer, and the originally received image frame is referred to as an enhancement layer. These two layers are coded separately, so as to provide better quality scalability. Therefore, based on the network condition and the user-end device capability, the most suitable bit-stream can be dynamically adjusted for transmission. Thus, video coding based on the SVC system has the prevalence of being suitable for transmission over networks.
The reduction of power consumption has long been an important issue in the development of video encoder because low power consumption allows the video encoder to work longer in the battery environment. Among others, the power consumed by accessing memory for reference data accounts for a very large portion of the total power consumption by the whole video encoder. However, in the prior art, only the power saving through single-layer memory data access is discussed, and the correlation between layers is not taken into consideration. Thus, it is an important issue for all types of inter-layer prediction coding to work out a way to increase the coding speed and reduce the memory data access through efficient data sharing, so as to achieve the target of low memory data access cost and power consumption.